With development of high speed vehicles and high performance vehicles, development of pneumatic tires having a low aspect ratio has been promoted and, in recent years, low aspect ratio tires having an aspect ratio of 50% or less have also been popularly used. However, in case of low aspect ratio tires, since the radial height of the sidewall portions thereof is small, the sidewall portions are greatly deformed so as to be sandwiched between a road and a rim flange when the tire falls into a large depression in a road or runs onto a projection such as curbstone on a road. Thus, tire damages such as cutting of carcass cords or separation of carcass cords from a rubber, i.e., so-called pinch cut, are easy to occur owing to bending occurring locally at the time of the deformation.
Accordingly, in conventional tires, it has been attempted to improve the pinch cut resistance by reinforcing a carcass which constitutes the framework of a tire in such a manner as forming the carcass from two carcass plies, both end portions of which are turned up around bead cores.